JP2012211892A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor capable of suppressing reduction of bond strength caused by a spark, and effectively preventing a stress by deformation of a gel member from applying to a diaphragm.SOLUTION: An opening area of a contact part with a gel member in pressure transfer paths (33, 43) is a minimum at an end part on the side of a sensor chip mounting surface (31), and larger than the opening area of the end part and a maximum at the part farthest from a diaphragm (23), and the opening area of an optional position is larger than an opening area at a position closer to the diaphragm (23) than the optional position. A support member (12) includes a first pressure transfer path (33), and has a first support member (30) for fixing a sensor chip (11) to the sensor chip mounting surface (31) through an adhesive (50). The opening area of the contact part with the gel member in the first pressure transfer path (33) is larger at the part farthest from the diaphragm (23) than at the end part on the side of the sensor chip mounting surface (31).

Description

  The present invention includes a sensor chip having a recess and a diaphragm in which gauge resistance is formed, a support member having a pressure transmission path communicating with the recess, a gel member that is integrally filled in the recess and the pressure transmission path, and a gel member The present invention relates to a pressure sensor in which a diaphragm is deformed in accordance with a pressure transmitted through the.

  Conventionally, as described in Patent Document 1, for example, a sensor chip having a recess and a diaphragm in which a gauge resistance is formed, a support member having a pressure transmission path communicating with the recess, the recess and the pressure transmission path are integrally filled. There is known a pressure sensor that includes a gel member that deforms a diaphragm according to pressure transmitted through the gel member.

  This type of pressure sensor is used to measure a differential pressure before and after an exhaust purification filter (DPF) provided in an exhaust pipe of a diesel engine vehicle, or to measure a pressure in an EGR atmosphere. For this reason, in order to protect a sensor chip from pressure media, such as a corrosive liquid and gas, the above-mentioned gel member is provided. Further, if moisture enters the recess of the sensor chip, it freezes at a low temperature and expands in volume, which may damage the diaphragm. For this reason, a gel member also plays the role which prevents a water | moisture content invading into a recessed part via the pressure transmission path of a supporting member.

JP 2007-3449 A

  In a pressure sensor in which a sensor chip is anodically bonded to a support member (stem) made of glass, anodic bonding is generally performed with the stem side as ground (low potential) and the sensor chip side as high potential. The diameter of the opening on the support member side in the recess of the sensor chip is smaller than the diameter of the opening on the sensor chip side in the pressure transmission path of the support member, and there is a shoulder portion that protrudes inside the pressure transmission path on the sensor chip Then, at the time of anodic bonding, the shoulder acts as a lightning rod, and current leaks from the shoulder. That is, a spark occurs. For this reason, stable anodic bonding cannot be performed, for example, the bonding strength decreases.

  On the other hand, in Patent Document 1, the diameter of the opening on the sensor chip side in the pressure transmission path formed in the stem is smaller than the diameter of the concave portion in the sensor chip, and the shoulder portion that protrudes inside the concave portion on the stem. An existing pressure sensor is shown. Thus, by providing a shoulder on the stem side, the occurrence of the spark can be prevented.

  By the way, the gel member used for the pressure sensor becomes hard at a low temperature, for example, −30 ° C. or less, and the gel member moves (flows) so as to relieve the stress, whereby the resistance value of the gauge resistance provided on the diaphragm is reduced. It is known that the sensor output characteristic changes. It is also conceivable that the sensor output characteristics fluctuate due to expansion of the gel member in a high temperature environment. In particular, when placed in an exhaust gas environment as described above, the surface layer of the gel member becomes hard when exposed to an acid component such as nitric acid contained in the exhaust gas for a long time. When the surface layer of the gel member becomes hard in this way, the sensor output will fluctuate greatly at a particularly high temperature compared to before the surface becomes hard.

  As described above, when the shoulder portion is provided on the stem side, when the gel member moves from the concave portion to the stem side, the viscous resistance of the gel member with respect to the stem is large, thereby inhibiting the movement of the gel member. On the other hand, the gel member can easily move from the stem side to the recess as compared with the configuration having the shoulder on the sensor chip side. Therefore, the gel member is relatively easy to move to the diaphragm side, and stress acts on the diaphragm. In the pressure sensor described in Patent Document 1, the diameter of the through hole formed in the stem is constant in the through direction.

  In view of the above problems, the present invention has an object to provide a pressure sensor capable of suppressing a decrease in bonding strength due to sparks and effectively suppressing stress due to deformation of a gel member from acting on a diaphragm. To do.

In order to achieve the above object, the pressure sensor according to claim 1 comprises:
A sensor chip (11) having a recess (22) that opens to one surface (21), a diaphragm (23) that forms the bottom of the recess (22), and a gauge resistor (24) formed in the diaphragm (23). )When,
A mounting surface (31) that faces one surface of the sensor chip (11) and to which the sensor chip (11) is fixed, and a pressure transmission path (33, 43) that opens to the mounting surface (31) and communicates with the recess (22). And a support member (12) having
A gel member (13) that is continuously filled from the recess (22) to at least part of the pressure transmission path (33, 43) and protects the diaphragm (23),
A pressure sensor in which the pressure of the pressure medium to be detected is transmitted to the diaphragm (23) via the gel member (13), and the resistance value of the gauge resistance (24) is changed by the deformation of the diaphragm (23). ,
The edge (34) of the pressure transmission path (33, 43) on the sensor chip mounting surface (31) of the support member (12) is a region (21a) surrounding the recess (22) on one surface (21) of the sensor chip (11). )
The opening area of the contact portion with the gel member in the pressure transmission path (33, 43) is the smallest at the end on the sensor chip mounting surface (31) side, and the opening area at the end farthest from the diaphragm (23). The opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm (23) than the arbitrary position,
The support member (12) includes a first pressure transmission path (33) that penetrates from the sensor chip mounting surface (31) to the back surface (32) and forms at least a part of the pressure transmission path (33, 43). A first support member (30) having a sensor chip (11) fixed to the sensor chip mounting surface (31) via an adhesive (50);
The opening area of the contact portion with the gel member in the first pressure transmission path (33) is larger in the portion farthest from the diaphragm (23) than the end on the sensor chip mounting surface (31) side,
The first support member is composed of a component (30) fixed to the sensor chip (11) only through the adhesive (50).

  Here, the viscous resistance also depends on the shape of the object in contact with the viscous member. Specifically, compared with a flat surface, a configuration having a convex portion or a concave portion has a larger contact area with the viscous member and a higher viscous resistance.

  In the present invention, the edge (34) of the pressure transmission path (33, 43) on the sensor chip mounting surface (31) of the support member (12) does not face the recess (22) of the sensor chip (11). This is opposed to a region (21a) surrounding the recess (22) on one surface (21) of the sensor chip (11). That is, in the direction parallel to the sensor chip mounting surface (31), the support member (12) does not have a shoulder portion that protrudes inside the recess (22). Therefore, when the gel member (13), which is a viscous member, is deformed hard at a low temperature and moves (flows) to relieve stress due to the deformation, the direction from the recess (22) to the support member (12), that is, the diaphragm. It is easy to move in the opposite direction to (23). Moreover, when a gel member expand | swells in a high temperature environment, a gel member (13) tends to move to the direction opposite to a diaphragm (23).

  Moreover, the opening area of the contact portion with the gel member (13) in the pressure transmission path (33, 43) is the minimum at the end on the sensor chip mounting surface (31) side, and the end at the portion farthest from the diaphragm (23). The opening area is larger and the maximum. Furthermore, the opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm (23) than the arbitrary position. For this reason, the gel member (13) easily moves in the direction opposite to the diaphragm (23) in the pressure transmission path (33, 43) of the support member (12).

  Further, the support member (12) has at least a first support member (30). This 1st support member (30) is comprised by the component fixed to the sensor chip (11) only through the adhesive material (50), ie, a single component. The opening area of the contact portion with the gel member (13) in the first pressure transmission path (33) is such that the portion farthest from the diaphragm (23) is more than the end on the sensor chip mounting surface (31) side. It is getting bigger. For this reason, the gel member (13) is likely to move in the direction opposite to the diaphragm (23) as compared with a configuration in which the opening area of the first pressure transmission path (33) is constant in the penetration direction.

  According to the present invention, due to the synergistic effect, it is possible to effectively suppress the stress due to the deformation of the gel member (13) from acting on the diaphragm (23) and thus the gauge resistance (24).

  In the present invention, the sensor chip (11) is not anodically bonded to the first support member (30), but is fixed through the adhesive (50), so that the pressure transmission path (33, 43) The edge (34) can be made to face one surface (21) of the sensor chip (11). In addition, since it is not adhesive bonding but anodic bonding while taking such arrangement | positioning, the fall of the joining strength by a spark can also be suppressed.

  The positional relationship between the edge (34) of the pressure transmission path (33, 43) and the region (21a) on the one surface (21) of the sensor chip (11) is, in other words, the pressure transmission path (33, 43). 43) and the edge (25) of the recess (22) on one surface (21) of the sensor chip (11) coincide with each other in a direction parallel to the sensor chip mounting surface (31). Or the edge (34) is located outside the edge (25).

  As described in claim 2, among the contact portions with the gel member (13) in the pressure transmission path (33, 43), at least the first pressure transmission path (33) has an opening area as the distance from the diaphragm (23) increases. It is preferable to have a configuration in which is increased.

  According to this, since the opening area of at least the first pressure transmission path (33) is larger as the distance from the diaphragm (23) is larger, the stress acting on the diaphragm (23) can be more effectively suppressed.

As described in claim 3, the inner wall surface (22 a) of the sensor chip (11) has an opening area of the recess (22) as the distance from the diaphragm (23) increases in the orthogonal direction perpendicular to the sensor chip mounting surface (31). Has a large taper shape,
The taper angle (θ2) of the inner wall surface (33a, 43a) of the pressure transmission path (33, 43) with respect to the orthogonal direction of the contact portion with the gel member (13) and the orthogonal direction of the inner wall surface (22a) of the recess (22) The taper angle (θ1) with respect to
The contact portion between the inner wall surface (22a) of the recess (22) of the sensor chip (11) and the gel member (13) on the inner wall surface (33a, 43a) of the pressure transmission path (33, 43) is made flush. It is good to have a configuration.

  According to this, the contact portion between the inner wall surface (22a) of the concave portion (22) and the gel member (13) on the inner wall surface (33a, 43a) of the pressure transmission path (33, 43) is in a flat state (step difference). It is a state without). Therefore, the gel member (13) easily moves in the direction away from the diaphragm (23). Thereby, the stress which acts on a diaphragm (23) can be suppressed more effectively.

  According to a fourth aspect of the present invention, a configuration may be adopted in which the contact portion of the inner wall surface (33a) of the first pressure transmission path (33) with the gel member (13) is stepped.

  Such a 1st support member (30) becomes a structure which has several area so that an opening area may mutually differ in the area where opening area is constant. For this reason, compared with the 1st support member (30) with which the contact part whole region of a gel member (13) has constant opening area, a gel member (13) moves easily in the direction away from a diaphragm (23).

  As described in claim 5, a ceramic multilayer substrate can be employed as the first support member (30). As described above, when the ceramic multilayer substrate is employed, the first pressure transmission path (33) having the opening shape can be easily formed as compared with, for example, a ceramic alone.

  As described in claim 6, it is preferable that the surface (13a) of the gel member (13) has a convex meniscus shape opposite to the diaphragm (23) at room temperature.

  According to this, even if the surface layer of the gel member (13) becomes hard due to, for example, an acid component in the exhaust gas, the concave meniscus shape and the surface (13a) have a flat shape opposite to the diaphragm (23). In comparison, the stress acting on the diaphragm (23) can be more effectively suppressed.

  As described in claim 7, the support member (12) communicates with the first pressure transmission path (33) and forms a pressure transmission path (33, 43) together with the first pressure transmission path (33). You may have a 2nd support member (40) provided with a transmission path (43) and supporting a 1st support member (30).

  When the second support member (40) is provided, the gel member (13) is continuously filled from the recess (22) to at least a part of the first pressure transmission path (33), for example, as in claim 8. It is preferable that the second pressure transmission path (43) is not filled.

  According to this, even if the surface layer of the gel member (13) is hardened by, for example, an acid component in the exhaust gas, the diaphragm is compared with the configuration in which the gel member (13) is filled up to the second pressure transmission path (43). The stress acting on (23) can be suppressed.

  As described in claim 9, the opening diameter of the portion of the pressure transmission path (33, 43) that is in contact with the gel member and farthest from the diaphragm (23) is larger than the thickness of the gel member (13). A configuration in which the length is longer may be used.

  According to this, even if the surface layer of the gel member (13) is hardened by an acid component in the exhaust gas, for example, the diaphragm (23) is compared with the configuration in which the thickness of the gel member (13) is equal to or larger than the opening diameter. It is possible to suppress the stress acting on.

It is sectional drawing which shows schematic structure of the pressure sensor which concerns on 1st Embodiment. As a comparative example, in a pressure sensor having a shoulder on the stem side and a constant opening area of the stem, it is a cross-sectional view showing a deformed state of the gel member. It is sectional drawing which shows the deformation | transformation state of a gel member in the pressure sensor shown in FIG. It is a figure which shows schematic structure of the pressure sensor used for stress analysis, (a) is the sample 1 which has a shoulder part on the sensor chip side like FIG. 1, (b) is a shoulder part on the stem side like FIG. 2 as a comparative example. Sample 2 is shown. It is a figure which shows the stress analysis result of the samples 1 and 2 shown in FIG. It is a figure which shows the relationship between the thickness of a gel member, and the variation | change_quantity of the stress which acts on a diaphragm. It is a figure which shows the relationship between the surface area of a gel member, and the variation | change_quantity of the stress which acts on a diaphragm. It is sectional drawing which shows a modification. It is sectional drawing which shows a modification. It is sectional drawing which shows a modification. It is sectional drawing which shows schematic structure of the pressure sensor which concerns on 2nd Embodiment. It is sectional drawing which shows a modification. It is sectional drawing which shows schematic structure of the pressure sensor which concerns on 3rd Embodiment. It is sectional drawing which shows the process of hardening a gel member among the manufacturing processes of the pressure sensor shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is provided to the part which is mutually the same or equivalent in each figure below. Moreover, also about a comparative example, the same code | symbol is provided to the part which is the same as that of embodiment of this invention, or is equivalent. In FIG. 4, for convenience, an adhesive layer that bonds the stem and the case is omitted. Further, the hatching of the gel member is omitted. 2, 3, and 8 to 10, the case is not shown for convenience.

(First embodiment)
The pressure sensor according to the present embodiment is used, for example, for pressure measurement of a corrosive pressure medium (liquid, gas, etc.). Specifically, it is used for measuring the pressure of exhaust gas in the exhaust pipe of a diesel engine vehicle, the differential pressure before and after the exhaust purification filter (DPF) provided in the exhaust pipe, the pressure in the EGR atmosphere, and the like.

  As shown in FIG. 1, the pressure sensor 10 includes a sensor chip 11 having a recess 22 as a main part, and a support member that supports the sensor chip 11 and has through holes 33 and 43 as pressure transmission paths. 12, a gel member 13 that is integrally filled in at least part of the recess 22 and the through holes 33 and 43, and an adhesive layer 50. The support member 12 includes at least a stem 30 as a first support member. In the present embodiment, the support member 12 includes not only the stem 30 but also a case 40 as a second support member on which the stem 30 is mounted. The adhesive layer 50 corresponds to the adhesive described in the claims.

  The sensor chip 11 is made of a semiconductor substrate or the like, and has a recess 22 that opens to the back surface 21 of the front surface 20 and the back surface 21. The back surface 21 corresponds to one surface described in the claims. The recess 22 is formed by etching the semiconductor substrate from the back surface 21 side. And the part which makes the bottom of the recessed part 22, ie, the thin part by the side of the surface 20 corresponding to the recessed part 22, becomes the diaphragm 23. FIG.

  In the present embodiment, a silicon substrate is used as the semiconductor substrate, and the recess 22 is formed by utilizing the difference in etching rate depending on the crystal plane. Specifically, the back surface 21 is the (100) surface, and anisotropic wet etching is performed using an etching solution such as KOH, so that the side surface of the inner wall surface 22a is the (111) surface and the bottom surface is the (100) surface. A recess 22 is formed. Such an inner wall surface 22a has an angle of 54.7 ° with respect to the back surface 21, that is, the (100) surface. In other words, the inner wall surface 22 a has a larger opening area of the recess 22 as it moves away from the diaphragm 23 in the direction perpendicular to the back surface 21, that is, in the depth direction of the recess 22. Specifically, it has a tapered shape in which the amount of change in the opening area with respect to the depth direction is constant.

  In addition, the code | symbol 25 shown in FIG. 1 is a 2nd inner edge part as an edge part (inner peripheral side edge part) of the recessed part 22 among the area | regions 21a surrounding the recessed part 22 in the back surface 21 of the sensor chip 11. FIG. In the back surface 21, the region 21 a surrounding the recess 22 refers to a region excluding the inner wall surface 22 a of the recess 22 on the surface opposite to the front surface 20 of the sensor chip 11. Since the recess 22 is formed by opening the back surface 21 of the sensor chip 11, the back surface 21 shown in the present embodiment does not include the inner wall surface 22 a of the recess 22. For this reason, the back surface 21 and the region 21a on the back surface 21 are substantially equivalent.

  Further, on the surface 20 of the sensor chip 11, a gauge resistor 24 formed by diffusing impurities, for example, is formed in the diaphragm 23. In the present embodiment, in order to increase the sensitivity, the gauge resistor 24 is formed in a portion of the diaphragm 23 where the distortion is large, for example, the peripheral portion of the diaphragm 23. At least four gauge resistors 24 are provided and constitute a bridge circuit (not shown).

  As described above, the sensor chip 11 of the present embodiment is configured as a semiconductor sensor chip, and a signal corresponding to the applied pressure is output by the gauge resistance effect. Specifically, the pressure of the pressure medium is transmitted to the gel member 13 through the through holes 33 and 43, and is transmitted to the diaphragm 23 through the gel member 13. Then, the diaphragm 23 is distorted (deformed) by the pressure, and the resistance value of the gauge resistor 24 changes due to the piezoresistance effect. A bridge circuit composed of the gauge resistor 24 outputs a signal corresponding to the strain of the diaphragm 23, that is, a signal having a level corresponding to the applied pressure value.

  The sensor chip 11 is placed on the sensor chip mounting surface 31 of the stem 30 with at least a part of the back surface 21 as a fixed part. And it is being fixed to the stem 30 by the contact bonding layer 50 arrange | positioned surrounding the recessed part 22. FIG. In the present embodiment, an adhesive film is employed as the adhesive layer 50. As described above, when the adhesive layer 50 formed in advance is employed, the adhesive sags into the recess 22 as in the example in which the liquid adhesive is cured by heat or light to form the adhesive layer 50. Generation | occurrence | production of malfunctions, such as adhering to the diaphragm 23, can be suppressed. In addition, a predetermined thickness can be secured as the adhesive layer 50.

  The stem 30 is also referred to as a pedestal, and includes a sensor chip mounting surface 31 that faces the back surface 21 of the sensor chip 11 and a through hole 33 as a first pressure transmission path that opens in the sensor chip mounting surface 31. Have. The through-hole 33 penetrates from the sensor chip mounting surface 31 to the back surface 32 thereof, and communicates with the recess 22 of the sensor chip 11 that is bonded and fixed to the stem 30.

The constituent material of the stem 30 is preferably a material having a linear expansion coefficient close to that of the substrate constituting the sensor chip 11 and having heat resistance depending on the application. For example, ceramics such as alumina (Al ₂ O ₃ ), metals such as 42 alloy and Cu, resins such as PPS and PBT, and glass can be employed. In the present embodiment, a ceramic multilayer substrate formed by laminating four layers of ceramic substrates is employed as the stem 30.

  In addition, of the sensor chip mounting surface 31 of the stem 30, the first inner edge portion 34 that surrounds the through hole 33 faces the back surface 21 (region 21 a) of the sensor chip 11. Here, the 1st inner edge part 34 is corresponded to the edge part of the pressure transmission path as described in a claim. The positional relationship between the first inner edge portion 34 and the back surface 21 of the sensor chip 11 is, in other words, the first inner edge portion 34 and the second inner edge portion 25 of the sensor chip 11 being parallel to the sensor chip mounting surface 31. Or the first inner edge 34 is located outside the second inner edge 25. Alternatively, the opening shape of the through hole 33 that opens in the sensor chip mounting surface 31 is equal to or greater than the opening shape of the recess 22 that opens in the back surface 21.

  Further, the opening area of the contact portion with the gel member 13 in the through hole 33 is the smallest at the end on the sensor chip mounting surface 31 side, that is, the first inner edge 34. Further, the opening area of the contact portion with the gel member 13 in the through hole 33 is larger than the first inner edge portion 34 in the portion farthest from the diaphragm 23. Furthermore, the opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm 23 than the arbitrary position.

  In the present embodiment, the first inner edge portion 34 is located outside the second inner edge portion 25 on the entire circumference. And the contact part with the gel member 13 in the inner wall surface 33a of the through-hole 33 is made into step shape, and, thereby, the opening area of the through-hole 33 is set in multiple steps. In the present embodiment, as described above, the ceramic multilayer substrate is adopted as the stem 30, and through holes are formed in each ceramic substrate constituting the stem 30. And the inner wall surface 33a is made into step shape by making the opening area of the through-hole of each ceramic board | substrate different from each other so that it may become large toward the case 40 side.

  The inner peripheral surface of the adhesive layer 50 is flush with the end surface of the ceramic substrate on the sensor chip 11 side of the ceramic multilayer substrate constituting the stem 30, and the adhesive layer 50 is on the back surface 21 of the sensor chip 11. Of these, the second inner edge portion 25 is in contact with a portion excluding a part of the range. For this reason, the second inner edge 25 of the sensor chip 11 is located on the inner side than the inner peripheral surface of the inner wall surface 33a and the adhesive layer 50, and a part of the back surface 21 (region 21a) of the sensor chip 11 is The stem 30 and the adhesive layer 50 are exposed.

  The stem 30 is placed on the stem mounting surface 41 of the case 40 so that the back surface 32 faces the case 40 and is fixed to the case 40 by an adhesive layer 51. That is, the adhesive layer 50, the stem 30, and the adhesive layer 51 are interposed between the case 40 and the sensor chip 11.

  The case 40 functions as an attachment portion for attaching the pressure sensor 10 to an appropriate position in the exhaust system of the vehicle, and penetrates through the stem mounting surface 41 and its back surface 42 as a second pressure transmission path. A hole 43 is provided. The through hole 43 communicates with the through hole 33 of the stem 30 that is bonded and fixed to the case 40. The case 40 has an external connection terminal (not shown).

  In addition, the third inner edge 44 that is the edge of the through hole 43 on the stem mounting surface 41 is the fourth inner edge that is the edge of the through hole 33 on the back surface 32 of the stem 30 in the direction parallel to the sensor chip mounting surface 31. It is located outside the portion 35. The through hole 43 has a constant straight shape in the direction perpendicular to the sensor chip mounting surface 31 (stem mounting surface 41). Thus, the opening area of the through hole 43 is larger than the opening area of the through hole 33.

  As a constituent material of the case 40, a material formed of a resin such as PPS or PBT, and a material in which a terminal such as a terminal is insert-molded can be employed. Further, the terminal of the case 40 and the sensor chip 11 are electrically connected by a bonding wire (not shown) or the like.

  As described above, in the pressure sensor 10, the stem 30 and the case 40 are integrated via the adhesive layer 51, and the support member 12 is configured. In the support member 12, the sensor chip 11 is bonded and fixed to the sensor chip mounting surface 31 of the stem 30. Further, the through hole 33 of the stem 30 and the through hole 43 of the case 40 communicate with each other, thereby forming a pressure transmission path of the support member 12. In this embodiment, the gel member 13 is filled in the through-hole 33 continuously from the recess 22 while filling the recess 22. That is, the gel member 13 is not in contact with the inner wall surface 43 a of the through hole 43 while having the case 40, and the gel member is formed in the recess 22 and the through hole 33, that is, in part of the pressure transmission paths 33 and 43. 13 is integrally filled.

  In the contact portions of the pressure transmission paths 33 and 43 with the gel member 13, the opening area is minimized at the first inner edge 34 of the stem 30. Further, it is the largest at the end face of the third layer ceramic substrate from the sensor chip 11 side, as shown in FIG. Furthermore, the opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm 23 than the arbitrary position.

  In the present embodiment, the opening area of the pressure transmission paths 33 and 43 is the smallest at the first inner edge 34 of the stem 30 and the largest at the inner wall surface 43 a of the through hole 43. Specifically, the relationship between the opening areas is such that the second inner edge 25 <the first inner edge 34 <the fourth inner edge 35 <the third inner edge 44. Furthermore, the opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm 23 than the arbitrary position.

  The gel member 13 is for protecting the diaphragm 23 and the adhesive layer 50 of the sensor chip 11 in particular. The gel member 13 covers the bottom surface portion of the recess 22 in the diaphragm 23. The pressure sensor 10 of the present embodiment is used for measuring the pressure of a corrosive pressure medium such as an exhaust gas pressure of a diesel engine. In particular, the diaphragm 23 (the bottom portion of the recess 22) and the adhesive layer 50 are protected.

  As a constituent material of the gel member 13, for example, a gel material such as silicone gel, fluorine gel, or fluorosilicone gel can be used. The gel member 13 is filled by injecting such a gel material into the recess 22 and the through-hole 33 and curing it.

  The gel member 13 is integrally filled at least partially from the recess 22 side among the entire recess 22 in the sensor chip 11 and the through holes 33 and 43 forming the pressure transmission path of the support member 12. In the present embodiment, as described above, it is continuously filled from the recess 22 to the middle of the through hole 33.

  Therefore, in the pressure sensor 10, when the pressure P1 of the pressure medium to be detected acts on the surface 13a (pressure receiving surface) of the gel member 13 exposed to the through hole 43 side through the through hole 43 of the case 40, Pressure is transmitted to the diaphragm 23 of the sensor chip 11 through the gel member 13 disposed in the through hole 33 and the recess 22.

  Moreover, in this embodiment, the surface 13a of the gel member 13 is convex at the diaphragm 23 side at room temperature, that is, has a concave bent shape on the opposite side to the diaphragm 23, that is, a so-called meniscus shape.

  Next, the effect of the characteristic part of the pressure sensor 10 according to the present embodiment will be described.

  First, in the present embodiment, the first inner edge 34 of the sensor chip mounting surface 31 of the stem 30 does not face the recess 22 of the sensor chip 11 but faces the back surface 21 of the sensor chip 11, that is, the region 21a. It is characterized by that. In other words, in the direction parallel to the sensor chip mounting surface 31, the stem 30 does not have a shoulder portion that protrudes inside the recess 22.

  In this way, the reason why the sensor chip 11 does not have a shoulder portion is that the sensor chip 11 is not anodically bonded to the stem 30 but is fixed through the adhesive layer 50. In the case of anodic bonding, if there is a shoulder portion that protrudes inside the through hole 33 forming the pressure transmission path in the sensor chip 11, the shoulder portion functions as a lightning rod, and current leaks from the shoulder portion. . That is, a spark occurs. For this reason, the support member 12 must have a shoulder portion that protrudes inside the recess 22.

  Here, the viscous resistance is proportional to the inherent viscosity coefficient (also referred to as the viscosity), and also depends on the shape of the object in contact with the viscous member. Specifically, compared with a flat surface, a configuration having a convex portion or a concave portion has a larger contact area with the viscous member and a higher viscous resistance.

  The gel member 13 that is a viscous member deforms hard at a low temperature (for example, −30 ° C. or lower). And it moves (flows) so as to relieve the stress caused by this deformation. In the pressure sensor 10 shown as a comparative example in FIG. 2, the stem 30 has a shoulder portion that protrudes inside the recess 22. In other words, the first inner edge 34 on the sensor chip mounting surface 31 of the stem 30 is positioned on the inner side of the second inner edge 25 on the back surface 21 of the sensor chip 11 and faces the recess 22 of the sensor chip 11. Yes. Thus, since the stem 30 has the shoulder portion, the viscous resistance of the gel member 13 with respect to the stem 30 is large when the gel member 13 moves from the concave portion 22 in the direction opposite to the diaphragm 23. For this reason, the movement of the gel member 13 in the opposite direction to the diaphragm 23 is hindered. On the other hand, with respect to the movement of the gel member 13 from the through hole 33 to the recess 22, since the shoulder portion is provided on the stem 30 side, the viscous resistance is smaller than the movement in the direction opposite to the diaphragm 23 from the recess 22. For this reason, the gel member 13 presses against the diaphragm 23, and stress acts on the diaphragm 23 as shown by the white arrow in FIG. 2, so that the diaphragm 23 is bent (distorted) in the opposite direction to the stem 30. The same applies when the gel member 13 expands in a high temperature environment.

  On the other hand, in this embodiment, as shown in FIG. 3, the stem 30 does not have a shoulder that protrudes inside the recess 22. For this reason, an increase in the viscous resistance due to the shoulder is suppressed, and the gel member 13 easily moves from the recess 22 toward the stem 30, that is, in the direction opposite to the diaphragm 23. On the other hand, for the movement of the gel member 13 from the through hole 33 to the concave portion 22 side, since the shoulder portion is provided on the sensor chip 11 side, the viscous resistance is compared with the movement from the concave portion 22 to the direction opposite to the diaphragm 23. Becomes bigger. In this way, the gel member 13 can easily move in the direction opposite to the diaphragm 23 as compared with the configuration shown in FIG. For this reason, the stress of the gel member 13 is relieved by the movement of the gel member 13 in the direction opposite to the diaphragm 23. And it can suppress effectively that the stress by the deformation | transformation of the gel member 13 acts on the diaphragm 23 and by extension, the gauge resistance 24. FIG.

  In addition, this inventor confirmed about the effect of the structure shown in the said embodiment by the analysis (FEM analysis) using the finite element method. FIG. 4 shows a schematic configuration of the pressure sensor used for the analysis. (A) is a sample 1 having a shoulder on the sensor chip 11 side, and (b) is a comparative example, like the pressure sensor 10 according to the present embodiment. The sample 2 which has a shoulder part in the stem 30 side as is shown. In sample 1 shown in FIG. 4A, the sensor chip 11 is a silicon substrate, the adhesive layer 50 is fluorosilicone, the stem 30 is alumina, the case 40 is PBT, and the gel member 13 is a fluorine-based gel having a Young's modulus of about 0.1 MPa. did. Moreover, the opening area of the stem 30 was made constant, and the distance along the sensor chip mounting surface 31 from the first inner edge portion 34 to the second inner edge portion 25 was 0.375 mm. Further, the inner wall surface 33a of the stem 30 and the inner peripheral surface of the adhesive layer 50 were flush with each other.

  On the other hand, in the sample 2 shown in FIG. 4B, the sensor chip 11 is a silicon substrate, the stem 30 is glass, the case 40 is PBT, and the gel member 13 is a fluorine-based gel having a Young's modulus of about 0.1 MPa. Further, the distance along the sensor chip mounting surface 31 from the first inner edge portion 34 to the second inner edge portion 25 was 0.7 mm, and the opening area of the stem 30 was constant.

  Further, regarding the configuration of the sensor chip 11 (the size and thickness of the diaphragm 23, the thickness of the sensor chip 11, the size and shape of the recess 22), and the configuration of the case 40 (opening area and length of the through-hole 43) The same for each sample. A structural analysis was performed on the stress generated in the diaphragm 23 when the temperature was changed from a high temperature of 150 ° C. to a low temperature of −40 ° C. In this analysis, the end portion 23a (two-dot chain line in FIG. 4) of the diaphragm 23 and the center CL of the diaphragm 23 are divided at equal distances, and the stress measurement points 1 to 15 having the end portion 23a as the point 1 are obtained. .

  The result is shown in FIG. As shown in FIG. 5, it is clear that the stress generated in the diaphragm 23 is smaller in the sample 1 than in the sample 2. The maximum stress generated at measurement points 1 to 15 was −0.5 MPa for sample 1 and −4.8 MPa for sample 2. Thus, the maximum generated stress of sample 1 is reduced by about 90% with respect to the maximum generated stress of sample 2. Also from this result, according to the configuration shown in the present embodiment, it is clear that the stress due to the deformation of the gel member 13 can be effectively suppressed from acting on the diaphragm 23 and, consequently, the gauge resistance 24.

  In the present embodiment, the opening area of the contact portion with the gel member 13 in the pressure transmission paths 33 and 43 is minimized at the first inner edge 34 of the stem 30. For this reason, there is no portion narrower than the end on the sensor chip mounting surface 31 side in the direction opposite to the diaphragm 23 than the end on the sensor chip mounting surface 31 side. Further, the opening area of the contact portion is larger than the opening area of the first inner edge 34 at the portion farthest from the diaphragm 23 and is the largest. Furthermore, the opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm 23 than the arbitrary position. For this reason, for example, when the gel member 13 is deformed hard at a low temperature and the stress due to this deformation is relieved, the gel member 13 easily moves in the through hole 33 of the stem 30 in the direction opposite to the diaphragm 23. Thereby, the stress which acts on the diaphragm 23 can be suppressed more effectively. The same applies when the gel member 13 expands in a high temperature environment. Moreover, the contact part with the gel member 13 is not the filling range of the gel member 13 at the time of manufacture, but the maximum of the range that the gel member 13 can take in the temperature range to be used. This is the portion where the expanded gel member 13 contacts at the upper limit of the use temperature at the substantially high temperature side.

  In the present embodiment, the sensor chip 11 is fixed to the stem 30 as the first support member via the adhesive layer 50. In other words, the first support member is configured only by the stem 30 that is a component to which the sensor chip 11 is fixed only through the adhesive layer 50. The opening area of the contact portion with the gel member 13 in the through hole 33 of the stem 30 is larger than the first inner edge 34 in the portion farthest from the diaphragm 23. As described above, the opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm 23 than the arbitrary position. For this reason, as shown in FIG. 3, in the stem 30, the gel member 13 easily moves in the direction opposite to the diaphragm 23 rather than the direction of the diaphragm 23. In other words, the gel member 13 can easily move in the direction opposite to the diaphragm 23 as compared with the stem 30 having a constant opening area of the through hole 33. Thereby, the stress which acts on the diaphragm 23 can be suppressed more effectively.

  As described above, according to the pressure sensor 10 according to the present embodiment, it is possible to effectively suppress the stress due to the deformation of the gel member 13 from acting on the diaphragm 23 and thus the gauge resistance 24 by the above synergistic effect.

  In particular, when placed in an exhaust gas environment like the pressure sensor 10 according to the present embodiment, the surface layer of the gel member 13 becomes hard when exposed to an acid component such as nitric acid contained in the exhaust gas for a long time. When the surface layer of the gel member 13 becomes hard as described above, the gel member 13 is less likely to move in the direction opposite to the diaphragm 23 as compared with a state in which the surface layer is not hard, and the force to push up the diaphragm 23 becomes stronger. . However, the pressure sensor 10 according to the present embodiment has a configuration in which the gel member 13 easily moves in the direction opposite to the diaphragm 23. Therefore, even if the surface layer of the gel member 13 is hardened by the acid component, the force to deform the surface layer of the gel member 13 hardened in the direction opposite to the diaphragm 23 is stronger than that of the conventional pressure sensor. Works. Thereby, the deformation amount of the surface layer portion of the hardened gel member 13 is increased, and the stress due to the deformation of the gel member 13 is prevented from acting on the diaphragm 23 and, consequently, the gauge resistance 24, as compared with the conventional pressure sensor. Can do.

  In addition, this inventor confirmed the influence of the thickness of the gel member 13, and the surface area about the fluctuation | variation amount by the presence or absence of the influence of the acid component of the stress which arises in the diaphragm 23 by the test. The results are shown in FIGS. In this test, a set of pressure sensors 10 having the same configuration is prepared, one of them is heated at 140 ° C., and pH 1.5 exhaust condensate is dropped on the surface 13a of the gel member 13 once every 20 to 30 minutes for 160 hours. did. Thereby, the sample with which the surface layer of the gel member 13 became hard was obtained. Then, this sample and a sample in which exhaust condensate is not dropped are taken as a set, and the diaphragm is divided into three levels: high temperature (HT) of 150 ° C., room temperature (RT) of 20 ° C., and low temperature (LT) of −40 ° C. Each of the 20 maximum stresses was measured and the difference was taken as the amount of variation. 6 and 7, the high temperature is indicated by a white triangle, the room temperature is indicated by a white square, and the low temperature is indicated by a white circle.

  Moreover, about the thickness of the gel member 13, the three levels of about 2.5 mm, 2.8 mm, and 3.2 mm were prepared. The sensor chip 11 was a silicon substrate, the adhesive layer 50 was fluorosilicone, the stem 30 was alumina, the case 40 was PBT, and the gel member 13 was a fluorine-based gel having a Young's modulus of about 0.1 MPa. The parameters other than the thickness of the gel member 13 were the same. As shown in FIG. 6, it was found that the amount of variation at a high temperature is large, and that the amount of variation is large as the thickness of the gel member 13 is particularly thick. As described above, the thicker the gel member 13 is, the larger the amount of fluctuation at high temperature is. The thicker the gel member 13 is, the larger the expansion force of the gel member 13 is, and this is considered to be because the force to push up the diaphragm 23 is increased. .

On the other hand, regarding the surface area of the gel member 13, two levels of 9 mm ² and 20 mm ² were prepared. The sensor chip 11 is a silicon substrate, the adhesive layer 50 is fluorosilicone, the stem 30 is alumina, the case 40 is PBT, and the gel member 13 is a fluorine-based gel having a Young's modulus of about 0.1 MPa. The parameters other than the surface area of the gel member 13 were the same. As shown in FIG. 7, it has been clarified that the amount of fluctuation is large as the amount of fluctuation at high temperatures is large, and in particular, the smaller the surface area of the gel member 13 is. As described above, the smaller the surface area of the gel member 13 is, the larger the amount of fluctuation at high temperature is. The smaller the surface area, in other words, the shorter the opening diameter, the stronger the spring of the hardened portion of the surface of the gel member 13 becomes. It becomes difficult to deform. For this reason, it is thought that the force which pushes up the diaphragm 23 becomes strong.

  From the above results, in order to suppress the stress acting on the diaphragm 23 due to the expansion of the gel member 13 while the surface layer of the gel member 13 is hardened by the acid component, the surface area of the gel member 13 is increased and the thickness is decreased. It is preferable to do. Regarding the thickness, since it is necessary to protect the adhesive layer 50 together with the diaphragm 23, the minimum thickness from the first inner edge 34 is required to be a thickness capable of protecting the adhesive layer 50, substantially about 1 mm.

  In the present embodiment, based on the above results, the gel member 13 is stopped from being filled up to the through hole 33 of the stem 30 while having the case 40 as the support member 12, so that the thickness of the gel member 13 is reduced. I have to. For this reason, compared with the structure with which the gel member 13 to the case 40 is filled, the stress which acts on the diaphragm 23, especially the stress when the surface layer of the gel member 13 becomes hard by an acid component can be suppressed. In addition, the opening diameter of the portion of the pressure transmission path 33, 43 that is in contact with the gel member 13 and farthest from the diaphragm 23 is longer than the thickness of the gel member 13. The thickness of the gel member 13 is the maximum length along the orthogonal direction. According to this, compared with the configuration in which the thickness of the gel member 13 is equal to or larger than the opening diameter, the stress acting on the diaphragm 23, particularly the stress when the surface layer of the gel member 13 becomes hard due to the acid component, is suppressed. can do. In this embodiment, a ceramic multilayer substrate is employed as the stem 30. As described above, when the ceramic multilayer substrate is employed, the through-hole 33 having the above-described opening shape can be easily formed as compared with the stem 30 made of a single ceramic.

(Modification)
In the above example, an example in which the contact portion with the gel member 13 in the through hole 33 of the stem 30 is stepped is shown. However, for example, as shown in FIG. 8, the contact area of the through-hole 33 with the gel member 13 may be configured such that the opening area is increased as the distance from the diaphragm 23 increases. In the example shown in FIG. 8, in the orthogonal direction orthogonal to the sensor chip mounting surface 31 (hereinafter simply referred to as the orthogonal direction), the amount of change in the opening area of the through hole 33 is a constant taper shape throughout the through hole 33. ing. As described above, when the opening area is large in the contact portion with the gel member 13 of the through-hole 33 as the distance from the diaphragm 23 increases, the gel member 13 easily moves in the direction opposite to the diaphragm 23 in the stem 30. Thereby, the stress which acts on the diaphragm 23 can be suppressed more effectively. Further, even when the surface layer of the gel member 13 is hardened by the acid component, due to the above configuration, for example, the stress acting on the diaphragm 23 is suppressed while suppressing an increase in the physique of the sensor chip 11 as compared with the stem 30 having a constant opening area. Can be suppressed. The stem 30 shown in FIG. 8 is a single piece of ceramic, resin, metal, or the like, but can also be realized with a ceramic multilayer substrate by tapering the end surfaces of the ceramic substrates constituting the ceramic multilayer substrate.

  Moreover, in the example shown in FIG. 8, the example with which the inclination with respect to the orthogonal direction of the inner wall face 22a of the recessed part 22 and the inner wall face 33a of the through-hole 33 differs was shown. That is, an example (θ2> θ1) is shown in which the taper angle θ1 with respect to the orthogonal direction of the inner wall surface 22a of the recess 22 and the taper angle θ2 with respect to the orthogonal direction of the inner wall surface 33a of the through hole 33 are different. However, as shown in FIG. 9, the taper angles θ <b> 1 and θ <b> 2 match, and the contact portion between the inner wall surface 22 a of the recess 22 of the sensor chip 11 and the gel member 13 on the inner wall surface 33 a of the through hole 33 is flush. It is good also as the structure made. In other words, the sensor chip 11 and the stem 30 may be bonded in a flat state without a step (unevenness). As described above, when the inner wall surface 22 a of the recess 22 and the contact portion of the inner wall surface 33 a of the through hole 33 with the gel member 13 are in a flat state, the gel member 13 easily moves in the direction opposite to the diaphragm 23. For this reason, the stress which acts on the diaphragm 23 can be suppressed further effectively. In FIG. 9, the surface including the adhesive layer 50 is flush, and the inner peripheral surface of the adhesive layer 50 has a tapered shape. It is also possible to adopt a configuration in which the inner wall surfaces 22a and 33a are not flush with each other even though the taper angles θ1 and θ2 are equal to each other.

  In the above example, the example in which the first inner edge portion 34 of the stem 30 is located outside the second inner edge portion 25 of the sensor chip 11 is shown. However, for example, as shown in FIG. 10, the first inner edge 34 and the second inner edge 25 may be configured to coincide with each other in the direction parallel to the sensor chip mounting surface 31. For example, in the example shown in FIG. 10, the opening area is constant from the end on the sensor chip mounting surface 31 side to the middle in the depth direction in the through-hole 33 of the stem 30, and the portion on the back surface 32 side from that is the diaphragm 23. The opening area increases as the distance from the center increases. In this case, since there is no level difference (unevenness) that is partly exposed from the second inner edge 25 of the back surface 21 in the bonding portion between the sensor chip 11 and the stem 30, the concave portion is formed when the gel member 13 moves. It is easy to move from 22 to the opposite direction of the diaphragm 23. Therefore, the stress acting on the diaphragm 23 can be more effectively suppressed.

  As shown in FIG. 9, in the configuration in which the inner wall surface 22 a of the recess 22, the inner peripheral surface of the adhesive layer 50, and the inner wall surface 33 a of the through hole 33 are flush with each other, the thickness of the adhesive layer 50 is reduced. The first inner edge portion 34 approaches the second inner edge portion 25, so that the two portions 25 and 34 substantially coincide with each other. 8-10 has shown the deformation | transformation state of the gel member 13, and the arrow in the gel member 13 has shown that the gel member 13 is easy to move to the through-hole 33 side from the recessed part 22. FIG. Also in FIGS. 8 to 10, the opening diameter of the portion of the pressure transmission path 33, 43 that is in contact with the gel member 13 and farthest from the diaphragm 23 is longer than the thickness of the gel member 13. .

(Second Embodiment)
In the present embodiment, description of portions common to the pressure sensor 10 shown in the above embodiment is omitted. In the first embodiment, an example in which the gel member 13 is filled continuously from the recess 22 to the through hole 33 of the stem 30 has been described.

  On the other hand, in this embodiment, as shown in FIG. 11, the first feature is that the gel member 13 is continuously filled from the recess 22 to the through hole 43 of the case 40. The second feature is that the third inner edge portion 44 surrounding the through hole 43 on the stem mounting surface 41 of the case 40 faces the back surface 32 of the stem 30. The pressure sensor 10 shown in FIG. 11 has the same configuration as the pressure sensor 10 shown in FIG. 1 of the first embodiment except for the filling range of the gel member 13. That is, the third inner edge portion 44 is positioned outside the fourth inner edge portion 35 that surrounds the through hole 33 on the back surface 32 of the stem 30. In addition, in FIG. 11, the deformation | transformation state of the gel member 13 is shown, The arrow in the gel member 13 shows that the gel member 13 is easy to move from the recessed part 22 to the through-hole 33 side and by extension, the through-hole 43 side. Yes.

  Thus, in this embodiment, like the stem 30 for the sensor chip 11, the case 40 does not have a shoulder portion that protrudes inside the through hole 33 of the stem 30. For this reason, the gel member 13 easily moves from the stem 30 toward the case 40. Therefore, the stress of the gel member 13 is relieved by the movement of the gel member 13 in the direction opposite to the diaphragm 23. And it can suppress effectively that the stress by the deformation | transformation of the gel member 13 acts on the diaphragm 23 and by extension, the gauge resistance 24. FIG.

  In the present embodiment, the through hole 43 of the case 40 has a straight shape with a larger opening area than the through hole 33 of the stem 30 and a constant opening area. Accordingly, as in the first embodiment, the opening area of the contact portion with the gel member 13 in the pressure transmission paths 33 and 43 is minimized at the first inner edge portion 34 of the stem 30. Further, the opening area of the contact portion is larger than the opening area of the first inner edge 34 at the portion farthest from the diaphragm 23 and is the largest. Furthermore, in the contact portion, the opening area at an arbitrary position is equal to or larger than the opening area at a position closer to the diaphragm 23 than the arbitrary position. For this reason, there can exist the same effect as a 1st embodiment.

  As in the first embodiment, the opening diameter of the portion of the pressure transmission path 33, 43 that is in contact with the gel member 13 and farthest from the diaphragm 23 is longer than the thickness of the gel member 13. Thereby, the stress which acts on the diaphragm 23, especially the stress when the surface layer of the gel member 13 is hardened by the acid component can be suppressed.

(Modification)
In the above example, the case 40 in which the opening area of the through hole 43 is constant is shown. However, the through hole 43 of the case 40 only needs to have an opening area at an arbitrary position equal to or larger than an opening area at a position closer to the diaphragm 23 than the arbitrary position in the contact portion of the gel member 13. For example, in the example shown in FIG. 12, the contact area of the inner wall surface 43 a of the through hole 43 with the gel member 13 increases the opening area of the through hole 43 as the distance from the diaphragm 23 increases. Specifically, the amount of change in the opening area of the through hole 43 is a tapered shape at the contact portion with the gel member 13. Further, the taper angle θ3 with respect to the orthogonal direction of the contact portion with the gel member 13 on the inner wall surface 43a of the through hole 43 coincides with the taper angles θ1 and θ2. In other words, in the support member 12, the taper angle of the contact portion with the gel member 13 is θ 2 (= θ 3), and this taper angle θ 2 matches the taper angle θ 1 of the sensor chip 11. The inner wall surface 22 a of the recess 22 of the sensor chip 11, the inner peripheral surface of the adhesive layer 50, and the inner wall surface 33 a of the through hole 33 of the stem 30 constituting the support member 12 are flush with each other. The contact portions of the wall surface 33a, the adhesive layer 51, and the inner wall surface 43a of the through hole 43 of the case 40 with the gel member 13 are flush with each other. With such a configuration, similarly to the modification of the first embodiment (see FIG. 9), the stress acting on the diaphragm 23 can be more effectively suppressed due to the taper shape effect and the flush effect. . In addition, since the surface area of the gel member 13 is larger than that of the through-hole 43 having a constant opening area, the stress acting on the diaphragm 23 can be suppressed while the surface layer of the gel member 13 is hardened by the acid component. it can. In FIG. 12, the deformed state of the gel member 13 is shown, and the arrow in the gel member 13 indicates that the gel member 13 can easily move from the concave portion 22 to the through hole 33 side and thus to the through hole 43 side. Yes. Also in FIG. 12, the opening diameter of the portion of the pressure transmission path 33, 43 that is in contact with the gel member 13 and farthest from the diaphragm 23 is longer than the thickness of the gel member 13.

  FIG. 12 shows an example in which the inner wall surface 43a of the through hole 43 has a taper shape partway through the through hole 43, and the remaining part has a straight shape with a constant opening area. However, in the configuration in which the gel member 13 is filled partway through the through hole 43, the entire inner wall surface 43a of the through hole 43 may have a shape in which the opening area of the through hole 43 increases as the distance from the diaphragm 23 increases.

  FIG. 12 illustrates an example in which the taper angles θ1, θ2, and θ3 are equal to each other, but a configuration in which the angles are different from each other may be employed. Furthermore, it is possible that two of the three taper angles θ1, θ2, and θ3 are equal and the remaining one is different. Further, it is possible to adopt a configuration in which the inner wall surfaces 22a, 33a, 43a are not flush with each other, although the taper angles θ1, θ2, θ3 are equal to each other. Furthermore, although the taper angles θ1, θ2, θ3 are equal to each other, it is possible to adopt a configuration in which the inner wall surfaces 22a, 33a are flush with each other and the inner wall surfaces 33a, 43a are not flush with each other.

  Moreover, although the 3rd inner edge part 44 showed the example located in the outer side rather than the 4th inner edge part 35, it is good also as a structure which the 3rd inner edge part 44 and the 4th inner edge part 35 correspond in a perimeter.

(Third embodiment)
In the present embodiment, description of portions common to the pressure sensor 10 shown in the above embodiment is omitted. In the said embodiment, the example (refer FIG. 1) by which the surface of the gel member 13 became concave meniscus shape on the opposite side to the diaphragm 23 was shown at room temperature.

  In contrast, the present embodiment is characterized in that the surface of the gel member 13 has a convex bent shape on the opposite side to the diaphragm 23, that is, a so-called meniscus shape, as shown in FIG. . The pressure sensor 10 shown in FIG. 13 is the same as the configuration shown in the first embodiment (see FIG. 1) except that the surface shape of the gel member 13 is different.

  As described above, when the surface of the gel member 13 has a convex meniscus shape on the opposite side to the diaphragm 23, the gel member 13 has the diaphragm 23 as compared to the concave meniscus shape and the flat surface opposite to the diaphragm 23. Easy to move to the opposite side. For example, consider a case where the surface layer of the gel member 13 becomes hard due to the acid component in the exhaust gas, and the hard portion of the surface layer is deformed in the direction opposite to the diaphragm 23 due to the expansion of the gel member 13. In this case, the hard part of the surface layer is more easily deformed to the side opposite to the diaphragm 23 than the concave meniscus shape or flat shape in the convex meniscus shape on the opposite side to the diaphragm 23. Therefore, the stress acting on the diaphragm 23 can be more effectively suppressed.

  For example, the following method can be considered to form the gel member 13 as shown in FIG. As shown in FIG. 14, the gel member 13 is injected from the recess 22 of the sensor chip 11 to the middle of the through hole 33 of the stem 30 through the through hole 43 of the case 40. Next, the gel member 13 is cured by heating, for example, in a state where the gel member 13 is pressurized from the surface 13a side, specifically, in a state where the pressure of the external atmosphere is higher than the atmospheric pressure. When the pressure is released after this curing treatment so that the atmospheric pressure is applied to the surface 13a of the gel member 13, the gel member 13 having a convex meniscus shape on the opposite side to the diaphragm 23 is obtained as shown in FIG. be able to.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In this embodiment, the example which the support member 12 consists of two members, the stem 30 as a 1st support member, and the case 40 as a 2nd support member was shown. However, the configuration of the support member 12 is not limited to the above example. What is necessary is just to provide a 1st support member at least. For example, a configuration having the case 40 as the first support member and not including the stem 30, that is, a so-called pedestal-less configuration may be employed. Further, the support member 12 may be configured by three or more members.

DESCRIPTION OF SYMBOLS 10 ... Pressure sensor 11 ... Sensor chip 12 ... Support member 13 ... Gel member 21 ... Back surface (one side)
22 ... concave portion 23 ... diaphragm 24 ... gauge resistance 25 ... first inner peripheral portion 30 ... stem (first support member)
31 ... Sensor chip mounting surface (mounting surface)
33 ... Through hole (first pressure transmission path)
40 ... Case (second support member)
43 ... Through hole (second pressure transmission path)
50 ... Adhesive layer (adhesive)

Claims (9)

A sensor chip (11) having a recess (22) that opens to one surface (21), a diaphragm (23) that forms the bottom of the recess (22), and a gauge resistor (24) formed in the diaphragm (23). )When,
A mounting surface (31) that faces one surface of the sensor chip (11) and to which the sensor chip is fixed, and a pressure transmission path (33, 43) that opens to the mounting surface and communicates with the recess (22). A support member (12) having
A gel member (13) that fills at least part of the pressure transmission path (33, 43) continuously from the recess (22) and protects the diaphragm (23),
The pressure sensor is a pressure sensor that transmits the pressure of the pressure medium to be detected to the diaphragm (23) via the gel member (13) and changes the resistance value of the gauge resistance (24) by the deformation of the diaphragm. And
An edge (34) of the pressure transmission path (33, 43) on the sensor chip mounting surface (31) of the support member (12) surrounds a recess (22) on one surface (21) of the sensor chip (11). Facing the region (21a),
The opening area of the contact portion with the gel member in the pressure transmission path (33, 43) is the smallest at the end on the sensor chip mounting surface (31) side, and the end at the portion farthest from the diaphragm (23). And the opening area at an arbitrary position is set to be equal to or larger than the opening area at a position closer to the diaphragm (23) than the arbitrary position,
The support member (12) penetrates from the sensor chip mounting surface (31) to the back surface (32), and forms at least a part of the pressure transmission path (33, 43). A first support member (30) having the sensor chip (11) fixed to the sensor chip mounting surface (31) via an adhesive (50),
The opening area of the contact portion with the gel member in the first pressure transmission path (33) is made larger in the portion farthest from the diaphragm (23) than the end on the sensor chip mounting surface (31) side. And
The pressure sensor according to claim 1, wherein the first support member is composed of a component (30) to which the sensor chip (11) is fixed only through the adhesive (50).   Among the contact parts with the gel member in the pressure transmission path (33, 43), at least the first pressure transmission path (33) has an opening area that is increased as the distance from the diaphragm (23) increases. The pressure sensor according to claim 1. The inner wall surface (22a) of the sensor chip (11) has a tapered shape in which the opening area of the recess (22) increases in the orthogonal direction perpendicular to the sensor chip mounting surface (31) as the distance from the diaphragm (23) increases. Have
The taper angle (θ2) of the contact portion with the gel member on the inner wall surface (33a, 43a) of the pressure transmission path (33, 43) with respect to the orthogonal direction, and the orthogonality of the inner wall surface (22a) of the recess (22). The taper angle (θ1) with respect to the direction matches,
The contact portion between the inner wall surface (22a) of the recess (22) of the sensor chip (11) and the gel member on the inner wall surface (33a, 43a) of the pressure transmission path (33, 43) is flush. The pressure sensor according to claim 2, wherein:   2. The pressure sensor according to claim 1, wherein a contact portion of the inner wall surface (33 a) of the first pressure transmission path (33) with the gel member has a step shape.   The pressure sensor according to any one of claims 2 to 4, wherein the first support member (30) is a ceramic multilayer substrate.   The pressure (1) according to any one of claims 1 to 5, wherein the surface (13a) of the gel member (13) has a convex meniscus shape opposite to the diaphragm (23) at room temperature. Sensor.   The support member (12) communicates with the first pressure transmission path (33) to form the second pressure transmission path (43) together with the first pressure transmission path (33). The pressure sensor according to any one of claims 1 to 6, further comprising a second support member (40) that supports the first support member (30).   The gel member (13) is continuously filled from the recess (22) to at least a part of the first pressure transmission path (33), and is not filled in the second pressure transmission path (43). The pressure sensor according to claim 7.   The opening diameter of the portion of the pressure transmission path (33, 43) in contact with the gel member and farthest from the diaphragm (23) is longer than the thickness of the gel member (13). The pressure sensor according to any one of claims 1 to 9.

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